1 /* 2 * XenBSD block device driver 3 * 4 * Copyright (c) 2010-2013 Spectra Logic Corporation 5 * Copyright (c) 2009 Scott Long, Yahoo! 6 * Copyright (c) 2009 Frank Suchomel, Citrix 7 * Copyright (c) 2009 Doug F. Rabson, Citrix 8 * Copyright (c) 2005 Kip Macy 9 * Copyright (c) 2003-2004, Keir Fraser & Steve Hand 10 * Modifications by Mark A. Williamson are (c) Intel Research Cambridge 11 * 12 * 13 * Permission is hereby granted, free of charge, to any person obtaining a copy 14 * of this software and associated documentation files (the "Software"), to 15 * deal in the Software without restriction, including without limitation the 16 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or 17 * sell copies of the Software, and to permit persons to whom the Software is 18 * furnished to do so, subject to the following conditions: 19 * 20 * The above copyright notice and this permission notice shall be included in 21 * all copies or substantial portions of the Software. 22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 23 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 24 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 25 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 26 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 27 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 28 * DEALINGS IN THE SOFTWARE. 29 * 30 * $FreeBSD$ 31 */ 32 33 #ifndef __XEN_BLKFRONT_BLOCK_H__ 34 #define __XEN_BLKFRONT_BLOCK_H__ 35 #include <xen/blkif.h> 36 37 /** 38 * Given a number of blkif segments, compute the maximum I/O size supported. 39 * 40 * \note This calculation assumes that all but the first and last segments 41 * of the I/O are fully utilized. 42 * 43 * \note We reserve a segement from the maximum supported by the transport to 44 * guarantee we can handle an unaligned transfer without the need to 45 * use a bounce buffer. 46 */ 47 #define XBD_SEGS_TO_SIZE(segs) \ 48 (((segs) - 1) * PAGE_SIZE) 49 50 /** 51 * Compute the maximum number of blkif segments requried to represent 52 * an I/O of the given size. 53 * 54 * \note This calculation assumes that all but the first and last segments 55 * of the I/O are fully utilized. 56 * 57 * \note We reserve a segement to guarantee we can handle an unaligned 58 * transfer without the need to use a bounce buffer. 59 */ 60 #define XBD_SIZE_TO_SEGS(size) \ 61 ((size / PAGE_SIZE) + 1) 62 63 /** 64 * The maximum number of outstanding requests blocks (request headers plus 65 * additional segment blocks) we will allow in a negotiated block-front/back 66 * communication channel. 67 */ 68 #define XBD_MAX_REQUESTS 256 69 70 /** 71 * The maximum mapped region size per request we will allow in a negotiated 72 * block-front/back communication channel. 73 */ 74 #define XBD_MAX_REQUEST_SIZE \ 75 MIN(MAXPHYS, XBD_SEGS_TO_SIZE(BLKIF_MAX_SEGMENTS_PER_REQUEST)) 76 77 /** 78 * The maximum number of segments (within a request header and accompanying 79 * segment blocks) per request we will allow in a negotiated block-front/back 80 * communication channel. 81 */ 82 #define XBD_MAX_SEGMENTS_PER_REQUEST \ 83 (MIN(BLKIF_MAX_SEGMENTS_PER_REQUEST, \ 84 XBD_SIZE_TO_SEGS(XBD_MAX_REQUEST_SIZE))) 85 86 /** 87 * The maximum number of shared memory ring pages we will allow in a 88 * negotiated block-front/back communication channel. Allow enough 89 * ring space for all requests to be XBD_MAX_REQUEST_SIZE'd. 90 */ 91 #define XBD_MAX_RING_PAGES \ 92 BLKIF_RING_PAGES(BLKIF_SEGS_TO_BLOCKS(XBD_MAX_SEGMENTS_PER_REQUEST) \ 93 * XBD_MAX_REQUESTS) 94 95 typedef enum { 96 XBDCF_Q_MASK = 0xFF, 97 /* This command has contributed to xbd_qfrozen_cnt. */ 98 XBDCF_FROZEN = 1<<8, 99 /* Freeze the command queue on dispatch (i.e. single step command). */ 100 XBDCF_Q_FREEZE = 1<<9, 101 /* Bus DMA returned EINPROGRESS for this command. */ 102 XBDCF_ASYNC_MAPPING = 1<<10, 103 XBDCF_INITIALIZER = XBDCF_Q_MASK 104 } xbdc_flag_t; 105 106 struct xbd_command; 107 typedef void xbd_cbcf_t(struct xbd_command *); 108 109 struct xbd_command { 110 TAILQ_ENTRY(xbd_command) cm_link; 111 struct xbd_softc *cm_sc; 112 xbdc_flag_t cm_flags; 113 bus_dmamap_t cm_map; 114 uint64_t cm_id; 115 grant_ref_t *cm_sg_refs; 116 struct bio *cm_bp; 117 grant_ref_t cm_gref_head; 118 void *cm_data; 119 size_t cm_datalen; 120 u_int cm_nseg; 121 int cm_operation; 122 blkif_sector_t cm_sector_number; 123 int cm_status; 124 xbd_cbcf_t *cm_complete; 125 }; 126 127 typedef enum { 128 XBD_Q_FREE, 129 XBD_Q_READY, 130 XBD_Q_BUSY, 131 XBD_Q_COMPLETE, 132 XBD_Q_BIO, 133 XBD_Q_COUNT, 134 XBD_Q_NONE = XBDCF_Q_MASK 135 } xbd_q_index_t; 136 137 typedef struct xbd_cm_q { 138 TAILQ_HEAD(, xbd_command) q_tailq; 139 uint32_t q_length; 140 uint32_t q_max; 141 } xbd_cm_q_t; 142 143 typedef enum { 144 XBD_STATE_DISCONNECTED, 145 XBD_STATE_CONNECTED, 146 XBD_STATE_SUSPENDED 147 } xbd_state_t; 148 149 typedef enum { 150 XBDF_NONE = 0, 151 XBDF_OPEN = 1 << 0, /* drive is open (can't shut down) */ 152 XBDF_BARRIER = 1 << 1, /* backend supports barriers */ 153 XBDF_FLUSH = 1 << 2, /* backend supports flush */ 154 XBDF_READY = 1 << 3, /* Is ready */ 155 XBDF_CM_SHORTAGE = 1 << 4, /* Free cm resource shortage active. */ 156 XBDF_GNT_SHORTAGE = 1 << 5, /* Grant ref resource shortage active */ 157 XBDF_WAIT_IDLE = 1 << 6 /* 158 * No new work until oustanding work 159 * completes. 160 */ 161 } xbd_flag_t; 162 163 /* 164 * We have one of these per vbd, whether ide, scsi or 'other'. 165 */ 166 struct xbd_softc { 167 device_t xbd_dev; 168 struct disk *xbd_disk; /* disk params */ 169 struct bio_queue_head xbd_bioq; /* sort queue */ 170 int xbd_unit; 171 xbd_flag_t xbd_flags; 172 int xbd_qfrozen_cnt; 173 int xbd_vdevice; 174 xbd_state_t xbd_state; 175 u_int xbd_ring_pages; 176 uint32_t xbd_max_requests; 177 uint32_t xbd_max_request_segments; 178 uint32_t xbd_max_request_blocks; 179 uint32_t xbd_max_request_size; 180 grant_ref_t xbd_ring_ref[XBD_MAX_RING_PAGES]; 181 blkif_front_ring_t xbd_ring; 182 xen_intr_handle_t xen_intr_handle; 183 struct gnttab_free_callback xbd_callback; 184 xbd_cm_q_t xbd_cm_q[XBD_Q_COUNT]; 185 bus_dma_tag_t xbd_io_dmat; 186 187 /** 188 * The number of people holding this device open. We won't allow a 189 * hot-unplug unless this is 0. 190 */ 191 int xbd_users; 192 struct mtx xbd_io_lock; 193 194 struct xbd_command *xbd_shadow; 195 }; 196 197 int xbd_instance_create(struct xbd_softc *, blkif_sector_t sectors, int device, 198 uint16_t vdisk_info, unsigned long sector_size); 199 200 static inline void 201 xbd_added_qentry(struct xbd_softc *sc, xbd_q_index_t index) 202 { 203 struct xbd_cm_q *cmq; 204 205 cmq = &sc->xbd_cm_q[index]; 206 cmq->q_length++; 207 if (cmq->q_length > cmq->q_max) 208 cmq->q_max = cmq->q_length; 209 } 210 211 static inline void 212 xbd_removed_qentry(struct xbd_softc *sc, xbd_q_index_t index) 213 { 214 sc->xbd_cm_q[index].q_length--; 215 } 216 217 static inline uint32_t 218 xbd_queue_length(struct xbd_softc *sc, xbd_q_index_t index) 219 { 220 return (sc->xbd_cm_q[index].q_length); 221 } 222 223 static inline void 224 xbd_initq_cm(struct xbd_softc *sc, xbd_q_index_t index) 225 { 226 struct xbd_cm_q *cmq; 227 228 cmq = &sc->xbd_cm_q[index]; 229 TAILQ_INIT(&cmq->q_tailq); 230 cmq->q_length = 0; 231 cmq->q_max = 0; 232 } 233 234 static inline void 235 xbd_enqueue_cm(struct xbd_command *cm, xbd_q_index_t index) 236 { 237 KASSERT(index != XBD_Q_BIO, 238 ("%s: Commands cannot access the bio queue.", __func__)); 239 if ((cm->cm_flags & XBDCF_Q_MASK) != XBD_Q_NONE) 240 panic("%s: command %p is already on queue %d.", 241 __func__, cm, cm->cm_flags & XBDCF_Q_MASK); 242 TAILQ_INSERT_TAIL(&cm->cm_sc->xbd_cm_q[index].q_tailq, cm, cm_link); 243 cm->cm_flags &= ~XBDCF_Q_MASK; 244 cm->cm_flags |= index; 245 xbd_added_qentry(cm->cm_sc, index); 246 } 247 248 static inline void 249 xbd_requeue_cm(struct xbd_command *cm, xbd_q_index_t index) 250 { 251 KASSERT(index != XBD_Q_BIO, 252 ("%s: Commands cannot access the bio queue.", __func__)); 253 if ((cm->cm_flags & XBDCF_Q_MASK) != XBD_Q_NONE) 254 panic("%s: command %p is already on queue %d.", 255 __func__, cm, cm->cm_flags & XBDCF_Q_MASK); 256 TAILQ_INSERT_HEAD(&cm->cm_sc->xbd_cm_q[index].q_tailq, cm, cm_link); 257 cm->cm_flags &= ~XBDCF_Q_MASK; 258 cm->cm_flags |= index; 259 xbd_added_qentry(cm->cm_sc, index); 260 } 261 262 static inline struct xbd_command * 263 xbd_dequeue_cm(struct xbd_softc *sc, xbd_q_index_t index) 264 { 265 struct xbd_command *cm; 266 267 KASSERT(index != XBD_Q_BIO, 268 ("%s: Commands cannot access the bio queue.", __func__)); 269 270 if ((cm = TAILQ_FIRST(&sc->xbd_cm_q[index].q_tailq)) != NULL) { 271 if ((cm->cm_flags & XBDCF_Q_MASK) != index) { 272 panic("%s: command %p is on queue %d, " 273 "not specified queue %d", 274 __func__, cm, 275 cm->cm_flags & XBDCF_Q_MASK, 276 index); 277 } 278 TAILQ_REMOVE(&sc->xbd_cm_q[index].q_tailq, cm, cm_link); 279 cm->cm_flags &= ~XBDCF_Q_MASK; 280 cm->cm_flags |= XBD_Q_NONE; 281 xbd_removed_qentry(cm->cm_sc, index); 282 } 283 return (cm); 284 } 285 286 static inline void 287 xbd_remove_cm(struct xbd_command *cm, xbd_q_index_t expected_index) 288 { 289 xbd_q_index_t index; 290 291 index = cm->cm_flags & XBDCF_Q_MASK; 292 293 KASSERT(index != XBD_Q_BIO, 294 ("%s: Commands cannot access the bio queue.", __func__)); 295 296 if (index != expected_index) { 297 panic("%s: command %p is on queue %d, not specified queue %d", 298 __func__, cm, index, expected_index); 299 } 300 TAILQ_REMOVE(&cm->cm_sc->xbd_cm_q[index].q_tailq, cm, cm_link); 301 cm->cm_flags &= ~XBDCF_Q_MASK; 302 cm->cm_flags |= XBD_Q_NONE; 303 xbd_removed_qentry(cm->cm_sc, index); 304 } 305 306 static inline void 307 xbd_initq_bio(struct xbd_softc *sc) 308 { 309 bioq_init(&sc->xbd_bioq); 310 } 311 312 static inline void 313 xbd_enqueue_bio(struct xbd_softc *sc, struct bio *bp) 314 { 315 bioq_insert_tail(&sc->xbd_bioq, bp); 316 xbd_added_qentry(sc, XBD_Q_BIO); 317 } 318 319 static inline void 320 xbd_requeue_bio(struct xbd_softc *sc, struct bio *bp) 321 { 322 bioq_insert_head(&sc->xbd_bioq, bp); 323 xbd_added_qentry(sc, XBD_Q_BIO); 324 } 325 326 static inline struct bio * 327 xbd_dequeue_bio(struct xbd_softc *sc) 328 { 329 struct bio *bp; 330 331 if ((bp = bioq_first(&sc->xbd_bioq)) != NULL) { 332 bioq_remove(&sc->xbd_bioq, bp); 333 xbd_removed_qentry(sc, XBD_Q_BIO); 334 } 335 return (bp); 336 } 337 338 static inline void 339 xbd_initqs(struct xbd_softc *sc) 340 { 341 u_int index; 342 343 for (index = 0; index < XBD_Q_COUNT; index++) 344 xbd_initq_cm(sc, index); 345 346 xbd_initq_bio(sc); 347 } 348 349 #endif /* __XEN_BLKFRONT_BLOCK_H__ */ 350